BISMARCK, N.D. — Residents in Valley City, population 6,500, were sandbagging Wednesday after forecasters said the Sheyenne River was coming in higher and faster than expected. The crest is now set for Thursday instead of Friday, and two feet higher than initially feared.

The town was getting offers of help from nearby Fargo, which only saw minor flooding before the Red River crested earlier this week.

Officials say the water is slowly dropping north of Fargo, where unprecedented overland flooding has left many rural residents isolated. Five Fargo homes sustained damage from the flood, most from pump failures.

In northwest North Dakota, meanwhile, authorities were weighing whether to drop half-ton sandbags from a National Guard helicopter to shore up a dam that stands between 30 endangered homes and the swollen Des Lacs River.

State Homeland Security Director Greg Wilz called it a "crapshoot'" because engineers say the sandbags could do more harm than good.

"At this stage of the game, it's more art than science," Wilz said.

About 200 people living near the river in Burlington had been advised to evacuate because the dam might fail, leading to a 2-foot to 3-foot rise on the river.

After touring the area, Gov. Jack Dalrymple said he was "amazed" at the flooding conditions.

"I wish we could say with certainty what's going to happen in the next day or so," he told worried residents in a packed Burlington city hall.

The National Weather Service issued a flash flood watch for the area on the west edge of Burlington, a city of about 1,200 people, saying a dam failure could lead to a 2-foot to 3-foot rise in the river.

Assistant Police Chief Bill Hunt said he was not aware of anyone leaving their home yet, and that officials in a boat already have rescued one person whose home was surrounded by floodwaters.

Authorities placed a video camera on the dam to monitor water levels and were prepared to immediately contact affected residents if the structure burst.

The dirt-and-rock Burlington Dam No. 1 was built in the 1930s to help control the river's flow as it meets the Souris River and flows around Burlington. Authorities have been trying to plug holes in the dam with sandbags but can no longer access the site for safety reasons.

Todd Sando, an engineer with the state of North Dakota, said "there is a very high potential it could wash out."

Hunt told The Associated Press that Federal Emergency Management Agency officials were bringing equipment to monitor the dam. Fire Chief Karter Lesmann said the city had about 3,000 sandbags on hand for use in the town.

An evacuation could become mandatory if the dam were to fail or if officials became certain it was about to fail, Hunt said. He said it was difficult to predict what sort of damage might result from a failure or how much time people would have to prepare for high water.

"It just depended on how it failed," he said. "If it completely failed, probably not much time ... if it eroded, we might have an hour or two."

Robert Kibler and his wife, Alex Deufel, decided to leave their home near the river on Tuesday but returned Wednesday to move their collection of 7,000 books to a main floor.

"We really need a new dam," said Kibler, who like his wife is a professor at Minot State University. "The one here is old. Hopefully this will spur someone to take action."

James MacPherson
/
AP

Josh Ishmael, left, and Will Mathews paddle to dry ground in Burlington, N.D., on Wednesday after shoring up their boss's home from the flooded Des Lacs River.

Josh Ishmael and Will Mathews, who are in North Dakota working on an oil pipeline, said they had been shoring up their boss's home with sandbags and a dike. They became stranded on the dike overnight this week and said they had to burn wood from a new deck on the home to keep warm, before authorities brought out a boat to rescue them.

"A large swath of the North Central United States is at risk of moderate to major flooding this spring," the National Weather Service said in its latest forecast on Feb. 24. Below are the scenarios by region.

North Central U.S.: above average

Emily M Rasinski
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St. Louis Post-Dispatch via AP

Ice backs up on the Mississippi River around the Clark Bridge in Alton, Ill., north of St. Louis, on Jan. 24.

The combination put a large portion of the North Central United States at risk of moderate to major flooding this spring, extending from northeastern Montana through western Wisconsin and along the Mississippi River south to St. Louis.

Information provided by NOAA on February 17, 2011, indicated Fargo, N.D., has a near 95 percent chance of exceeding major flood stage of 30 feet. At a stage of 30 feet, portions of downtown Fargo begin flooding and temporary dike construction is necessary. Approximately a 20 percent chance exists of reaching or exceeding the 40.8 foot record set in 2009. Grand Forks, N.D., has about a 95 percent chance of exceeding major flood stage of 46 feet. There is approximately a 40 percent chance of Devils Lake, N.D., exceeding 1,455 feet, which could partially inundate portions of the town of Minnewauken, including critical infrastructure and roads across the lake, emergency service routes and possibly a small section of the Amtrak train line.

There is potential for moderate to major flooding on the Milk River and its tributaries in northeastern Montana. The Milk River near Glasgow Montana has about a 90 percent chance of exceeding the major flood stage of 27 feet. Some minor ice jam flooding is already occurring in Montana; additional flooding resulting from ice jams is likely throughout the late winter and early spring.

The James River at Huron, S.D., has about a 90 percent chance of exceeding major flood stage of 15 feet and a 30 percent chance of exceeding the record 21.2 foot level set in 1997. The Big Sioux River at Brookings, S.D., has a greater than 95 percent chance of exceeding major flood stage of 12 feet and about a 30 percent chance of exceeding the 14.77-foot record set in 1969.

The Mississippi River is likely to see major flooding from its headwaters near St. Paul, Minnesota, downstream to St. Louis. St. Paul, MN., has about a 95 percent chance of exceeding major flood stage of 17 feet, where secondary flood walls are deployed to protect the St. Paul Airport. Further downstream, the risk of major flooding on the Mississippi (Iowa, Illinois and Missouri borders) will persist into the spring. Much of that region’s snowpack typically accumulates later in the winter. The quantity of spring rains and late-season snow will determine the magnitude of flooding in the Middle Mississippi Valley.

The Hudson-Athens Lighthouse is frozen in ice on the Hudson River and in front of the Catskill Mountains in Hudson, N.Y., on Jan. 14.

There is a small area of above average flood risk in portions of the Northeast, primarily across Southern New England and the Catskills Mountains in N.Y. state. As a result of October and November rain storms, these regions had above normal soil moisture levels prior to the winter freeze, followed by above average snowfall, and river icing in many locations.

If snowpack and river icing conditions were to persist beyond mid-March, this area could have an elevated risk of spring flooding during the melt period, especially if heavy rains fall during the melt.

Southern plains: below average

Eric Gay
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AP

An irrigation system is used to bring water to a dry field near Hondo, Texas on Dec. 15.

Farmer Aries Haygood shows how dry the top layer of soil is on his freshly planted onion farm in Lyons, Ga., on Dec. 10.

Fall and winter precipitation over the Mid Atlantic and Southeast ranged from 50 to 75 percent of average for this period. Isolated portions of South and North Carolina only received between 25 and 50 percent of normal precipitation. Therefore, soil moisture is well below normal across most of the Southeastern US and the Mid-Atlantic.

Deficits in the precipitation and soil moisture water contents translate into below average stream flow conditions for much of the region and a below average flood risk for the spring.

A utility worker restores service to homes around Lake Tahoe, Calif., on Dec. 20 after a storm that dumped up to 10 feet of snow in places.

Late February is too early to determine spring flooding potential across the Western U.S. Much of the snowfall which determines spring runoff in the mountain west accumulates during the remainder of the winter and spring.

Snowpack remains above and much above average in many regions. However, extreme high temperature can lead to elevated melt rates at any time during spring. There is still ample time left in the accumulation period for the spring flood potential to change.